semmutex-linux.cpp@ 62514

Last change on this file since 62514 was 62477, checked in by vboxsync, 8 years ago
(C) 2016
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1	/* $Id: semmutex-linux.cpp 62477 2016-07-22 18:27:37Z vboxsync $ */
2	/** @file
3	* IPRT - Mutex Semaphore, Linux (2.6.x+).
4	*/
5
6	/*
7	* Copyright (C) 2006-2016 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*********************************************************************************************************************************
29	* Header Files *
30	*********************************************************************************************************************************/
31	#include <iprt/semaphore.h>
32	#include "internal/iprt.h"
33
34	#include <iprt/alloc.h>
35	#include <iprt/asm.h>
36	#include <iprt/assert.h>
37	#include <iprt/err.h>
38	#include <iprt/lockvalidator.h>
39	#include <iprt/thread.h>
40	#include <iprt/time.h>
41	#include "internal/magics.h"
42	#include "internal/strict.h"
43
44	#include <errno.h>
45	#include <limits.h>
46	#include <pthread.h>
47	#include <unistd.h>
48	#include <sys/time.h>
49	#include <sys/syscall.h>
50	#if 0 /* With 2.6.17 futex.h has become C++ unfriendly. */
51	# include <linux/futex.h>
52	#else
53	# define FUTEX_WAIT 0
54	# define FUTEX_WAKE 1
55	#endif
56
57
58	/*********************************************************************************************************************************
59	* Structures and Typedefs *
60	*********************************************************************************************************************************/
61	/**
62	* Linux internal representation of a Mutex semaphore.
63	*/
64	struct RTSEMMUTEXINTERNAL
65	{
66	/** The futex state variable.
67	* 0 means unlocked.
68	* 1 means locked, no waiters.
69	* 2 means locked, one or more waiters.
70	*/
71	int32_t volatile iState;
72	/** Nesting count. */
73	uint32_t volatile cNestings;
74	/** The owner of the mutex. */
75	pthread_t volatile Owner;
76	/** Magic value (RTSEMMUTEX_MAGIC). */
77	uint32_t volatile u32Magic;
78	#ifdef RTSEMMUTEX_STRICT
79	/** Lock validator record associated with this mutex. */
80	RTLOCKVALRECEXCL ValidatorRec;
81	#endif
82	};
83
84
85
86	/**
87	* Wrapper for the futex syscall.
88	*/
89	static long sys_futex(int32_t volatile uaddr, int op, int val, struct timespec utime, int32_t *uaddr2, int val3)
90	{
91	errno = 0;
92	long rc = syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3);
93	if (rc < 0)
94	{
95	Assert(rc == -1);
96	rc = -errno;
97	}
98	return rc;
99	}
100
101
102	#undef RTSemMutexCreate
103	RTDECL(int) RTSemMutexCreate(PRTSEMMUTEX phMutexSem)
104	{
105	return RTSemMutexCreateEx(phMutexSem, 0 /fFlags/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
106	}
107
108
109	RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags,
110	RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
111	{
112	AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
113
114	/*
115	* Allocate semaphore handle.
116	*/
117	struct RTSEMMUTEXINTERNAL pThis = (struct RTSEMMUTEXINTERNAL )RTMemAlloc(sizeof(struct RTSEMMUTEXINTERNAL));
118	if (pThis)
119	{
120	pThis->u32Magic = RTSEMMUTEX_MAGIC;
121	pThis->iState = 0;
122	pThis->Owner = (pthread_t)~0;
123	pThis->cNestings = 0;
124	#ifdef RTSEMMUTEX_STRICT
125	if (!pszNameFmt)
126	{
127	static uint32_t volatile s_iMutexAnon = 0;
128	RTLockValidatorRecExclInit(&pThis->ValidatorRec, hClass, uSubClass, pThis,
129	!(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL),
130	"RTSemMutex-%u", ASMAtomicIncU32(&s_iMutexAnon) - 1);
131	}
132	else
133	{
134	va_list va;
135	va_start(va, pszNameFmt);
136	RTLockValidatorRecExclInitV(&pThis->ValidatorRec, hClass, uSubClass, pThis,
137	!(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), pszNameFmt, va);
138	va_end(va);
139	}
140	#endif
141
142	*phMutexSem = pThis;
143	return VINF_SUCCESS;
144	}
145
146	return VERR_NO_MEMORY;
147	}
148
149
150	RTDECL(int) RTSemMutexDestroy(RTSEMMUTEX hMutexSem)
151	{
152	/*
153	* Validate input.
154	*/
155	if (hMutexSem == NIL_RTSEMMUTEX)
156	return VINF_SUCCESS;
157	struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
158	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
159	AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC,
160	("hMutexSem=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
161	VERR_INVALID_HANDLE);
162
163	/*
164	* Invalidate the semaphore and wake up anyone waiting on it.
165	*/
166	ASMAtomicWriteU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD);
167	if (ASMAtomicXchgS32(&pThis->iState, 0) > 0)
168	{
169	sys_futex(&pThis->iState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
170	usleep(1000);
171	}
172	pThis->Owner = (pthread_t)~0;
173	pThis->cNestings = 0;
174	#ifdef RTSEMMUTEX_STRICT
175	RTLockValidatorRecExclDelete(&pThis->ValidatorRec);
176	#endif
177
178	/*
179	* Free the semaphore memory and be gone.
180	*/
181	RTMemFree(pThis);
182	return VINF_SUCCESS;
183	}
184
185
186	RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass)
187	{
188	#ifdef RTSEMMUTEX_STRICT
189	/*
190	* Validate.
191	*/
192	RTSEMMUTEXINTERNAL *pThis = hMutexSem;
193	AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
194	AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
195
196	return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass);
197	#else
198	return RTLOCKVAL_SUB_CLASS_INVALID;
199	#endif
200	}
201
202
203	DECL_FORCE_INLINE(int) rtSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, bool fAutoResume, PCRTLOCKVALSRCPOS pSrcPos)
204	{
205	/*
206	* Validate input.
207	*/
208	struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
209	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
210	AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
211
212	/*
213	* Check if nested request.
214	*/
215	pthread_t Self = pthread_self();
216	if ( pThis->Owner == Self
217	&& pThis->cNestings > 0)
218	{
219	#ifdef RTSEMMUTEX_STRICT
220	int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorRec, pSrcPos);
221	if (RT_FAILURE(rc9))
222	return rc9;
223	#endif
224	ASMAtomicIncU32(&pThis->cNestings);
225	return VINF_SUCCESS;
226	}
227
228	#ifdef RTSEMMUTEX_STRICT
229	RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
230	if (cMillies)
231	{
232	int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorRec, hThreadSelf, pSrcPos, cMillies);
233	if (RT_FAILURE(rc9))
234	return rc9;
235	}
236	#else
237	RTTHREAD hThreadSelf = RTThreadSelf();
238	#endif
239
240	/*
241	* Convert timeout value.
242	*/
243	struct timespec ts;
244	struct timespec *pTimeout = NULL;
245	uint64_t u64End = 0; /* shut up gcc */
246	if (cMillies != RT_INDEFINITE_WAIT)
247	{
248	ts.tv_sec = cMillies / 1000;
249	ts.tv_nsec = (cMillies % 1000) * UINT32_C(1000000);
250	u64End = RTTimeSystemNanoTS() + cMillies * UINT64_C(1000000);
251	pTimeout = &ts;
252	}
253
254	/*
255	* Lock the mutex.
256	* Optimize for the uncontended case (makes 1-2 ns difference).
257	*/
258	if (RT_UNLIKELY(!ASMAtomicCmpXchgS32(&pThis->iState, 1, 0)))
259	{
260	for (;;)
261	{
262	int32_t iOld = ASMAtomicXchgS32(&pThis->iState, 2);
263
264	/*
265	* Was the lock released in the meantime? This is unlikely (but possible)
266	*/
267	if (RT_UNLIKELY(iOld == 0))
268	break;
269
270	/*
271	* Go to sleep.
272	*/
273	if (pTimeout && ( pTimeout->tv_sec \|\| pTimeout->tv_nsec ))
274	{
275	#ifdef RTSEMMUTEX_STRICT
276	int rc9 = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true,
277	cMillies, RTTHREADSTATE_MUTEX, true);
278	if (RT_FAILURE(rc9))
279	return rc9;
280	#else
281	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_MUTEX, true);
282	#endif
283	}
284
285	long rc = sys_futex(&pThis->iState, FUTEX_WAIT, 2, pTimeout, NULL, 0);
286
287	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX);
288	if (RT_UNLIKELY(pThis->u32Magic != RTSEMMUTEX_MAGIC))
289	return VERR_SEM_DESTROYED;
290
291	/*
292	* Act on the wakup code.
293	*/
294	if (rc == -ETIMEDOUT)
295	{
296	Assert(pTimeout);
297	return VERR_TIMEOUT;
298	}
299	if (rc == 0)
300	/* we'll leave the loop now unless another thread is faster */;
301	else if (rc == -EWOULDBLOCK)
302	/* retry with new value. */;
303	else if (rc == -EINTR)
304	{
305	if (!fAutoResume)
306	return VERR_INTERRUPTED;
307	}
308	else
309	{
310	/* this shouldn't happen! */
311	AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno));
312	return RTErrConvertFromErrno(rc);
313	}
314
315	/* adjust the relative timeout */
316	if (pTimeout)
317	{
318	int64_t i64Diff = u64End - RTTimeSystemNanoTS();
319	if (i64Diff < 1000)
320	{
321	rc = VERR_TIMEOUT;
322	break;
323	}
324	ts.tv_sec = (uint64_t)i64Diff / UINT32_C(1000000000);
325	ts.tv_nsec = (uint64_t)i64Diff % UINT32_C(1000000000);
326	}
327	}
328
329	/*
330	* When leaving this loop, iState is set to 2. This means that we gained the
331	* lock and there are _possibly_ some waiters. We don't know exactly as another
332	* thread might entered this loop at nearly the same time. Therefore we will
333	* call futex_wakeup once too often (if _no_ other thread entered this loop).
334	* The key problem is the simple futex_wait test for x != y (iState != 2) in
335	* our case).
336	*/
337	}
338
339	/*
340	* Set the owner and nesting.
341	*/
342	pThis->Owner = Self;
343	ASMAtomicWriteU32(&pThis->cNestings, 1);
344	#ifdef RTSEMMUTEX_STRICT
345	RTLockValidatorRecExclSetOwner(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true);
346	#endif
347	return VINF_SUCCESS;
348	}
349
350
351	#undef RTSemMutexRequest
352	RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
353	{
354	#ifndef RTSEMMUTEX_STRICT
355	int rc = rtSemMutexRequest(hMutexSem, cMillies, true, NULL);
356	#else
357	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
358	int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos);
359	#endif
360	Assert(rc != VERR_INTERRUPTED);
361	return rc;
362	}
363
364
365	RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
366	{
367	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
368	int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos);
369	Assert(rc != VERR_INTERRUPTED);
370	return rc;
371	}
372
373
374	#undef RTSemMutexRequestNoResume
375	RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
376	{
377	#ifndef RTSEMMUTEX_STRICT
378	return rtSemMutexRequest(hMutexSem, cMillies, false, NULL);
379	#else
380	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
381	return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos);
382	#endif
383	}
384
385
386	RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
387	{
388	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
389	return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos);
390	}
391
392
393	RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMutexSem)
394	{
395	/*
396	* Validate input.
397	*/
398	struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
399	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
400	AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
401
402	#ifdef RTSEMMUTEX_STRICT
403	int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorRec, pThis->cNestings == 1);
404	if (RT_FAILURE(rc9))
405	return rc9;
406	#endif
407
408	/*
409	* Check if nested.
410	*/
411	pthread_t Self = pthread_self();
412	if (RT_UNLIKELY( pThis->Owner != Self
413	\|\| pThis->cNestings == 0))
414	{
415	AssertMsgFailed(("Not owner of mutex %p!! Self=%08x Owner=%08x cNestings=%d\n",
416	pThis, Self, pThis->Owner, pThis->cNestings));
417	return VERR_NOT_OWNER;
418	}
419
420	/*
421	* If nested we'll just pop a nesting.
422	*/
423	if (pThis->cNestings > 1)
424	{
425	ASMAtomicDecU32(&pThis->cNestings);
426	return VINF_SUCCESS;
427	}
428
429	/*
430	* Clear the state. (cNestings == 1)
431	*/
432	pThis->Owner = (pthread_t)~0;
433	ASMAtomicWriteU32(&pThis->cNestings, 0);
434
435	/*
436	* Release the mutex.
437	*/
438	int32_t iNew = ASMAtomicDecS32(&pThis->iState);
439	if (RT_UNLIKELY(iNew != 0))
440	{
441	/* somebody is waiting, try wake up one of them. */
442	ASMAtomicXchgS32(&pThis->iState, 0);
443	(void)sys_futex(&pThis->iState, FUTEX_WAKE, 1, NULL, NULL, 0);
444	}
445	return VINF_SUCCESS;
446	}
447
448
449	RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem)
450	{
451	/*
452	* Validate.
453	*/
454	RTSEMMUTEXINTERNAL *pThis = hMutexSem;
455	AssertPtrReturn(pThis, false);
456	AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, false);
457
458	return pThis->Owner != (pthread_t)~0;
459	}
460

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source: vbox/trunk/src/VBox/Runtime/r3/linux/semmutex-linux.cpp@ 62514

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